Saturday, February 13, 2010

Almost three years after COURAGE and still too many stents?

The cardiologists truly mean well, and care deeply about their patients. But, I believe they do too much stenting...

That may be true but the WSJ piece does not prove the case. Unfortunately the article, all too typical of medical news reporting in popular media, is simplistic and deceptive. It cites data for the total number of stents. Stenting for stable angina, which is what COURAGE addressed, accounts for less than a third of those stents. By far most stents are implanted for acute coronary syndromes. Moreover COURAGE looked at a select group of people with very stable and clinically mild CAD. So the number of stents addressed by COURAGE is probably far less than a third of the total.

Also consider that more than 30% of the patients in the medical treatment arm of COURAGE, which used an intention to treat analysis, crossed over to revascularization. Similar finding in BARI 2D. That means that for 30% or more of stable angina patients you treat conservatively all you can hope to do is postpone their revascularization, according to the best evidence from two prospective randomized controlled trials.

So, the actual number of stent implants that were influenced by COURAGE cannot be determined from the data cited by WSJ, as those implants are diluted by the much larger number of patients stented for ACS.

Also, the WSJ article provides only a graph (no numeric data and no indication of statistical significance) and no link to the primary source. I went to the Millennium web site and could not find the raw data. Graphs can give a distorted impression but it looks as though the number of stent implantations is still down from the pre-COURAGE peak.

Why did the number of stents drift upward again after the initial drop following the COURAGE announcement? Certainly old habits tend to recur over time but the crossover I alluded to above may also be a factor.

The poor uptake of best evidence has been known a long time and practice patterns following COURAGE are no exception, but this Wall Street Journal article gives a very distorted picture of what's going on.